1. Technical Field
The present invention relates to an input/output (input-output) system that includes a sheet-like input/output unit into which wiring is embedded or onto which wiring is stuck, and a connection box that is attached to the input/output unit.
2. Description of the Related Art
Electric carpets, electric blankets and electric underblankets are products that use a sheet-like member as an output unit and in the sheet-like output unit, wiring is embedded. In such products, a control box is attached to an edge of the sheet-like output unit as a connection box for controlling the power supplied to an embedded heater via the wiring. The connection box has a control function and/or a connection function. A housing of the connection box is divided into an upper housing and a lower housing so as to form a slit into which the output unit is fitted. The connection box is fixed onto the sheet-like output unit by hooks or projections that are provided on the upper and/or lower edges of the slit through which the output unit passes and grasp the output unit.
Electric carpets, electric blankets, and electric underblankets are all relatively thick and are extremely soft. This means that even if the sheet-like output unit is grasped by the hooks or projections, there is little risk of damage to the wiring embedded inside the wiring unit. There is also no risk of damage to the sheet-like output unit itself.
In recent years, sensor sheets, in which a plurality of sensors, such as pressure sensors, are embedded have been introduced. A sheet-like base material of the sensor sheet is a plastic sheet that is thin and soft, and relatively firm so as to be able to maintain its shape to a certain degree. By such a characteristic base material, thin semiconductor materials that operate as the pressure sensors are supported and disposed at predetermined intervals so that specified surfaces of the pressure sensors are oriented in a specified direction. The sensor sheet on which a plurality of pressure sensors are disposed can be used as a biological information detection apparatus that detects and/or monitors the breathing of a user on a bed. When spread on a bed and lain upon by a user, the biological information detection system including the sensor sheets can determine the biological or living state of the user by analyzing the output of the pressure sensors on the sensor sheets. This means by using a biological information detection system in a hospital it is possible to detect whether a gravely ill patient is breathing during emergencies and to measure the number of times a patient suspected of sleep apnea syndrome stops breathing during his or her sleep.
The biological or biomedical information detection system is one of input apparatus that uses a sensor sheet as an input unit, a connection box with a control and/or a connection function for receiving an input of signals from the sensors via the wiring of the input unit is required. In an input apparatus for receiving important information such as the biological information detection apparatus, damage and breakages of the wiring have a large effect on the reliability of apparatus or system. On the other hand, when bed making or the system is not in use, it is important to be able to fold up the sheet-like input unit (sensor sheet) since the sheet occupies large area. When the sensor sheet is folded up, the boundary part of the connection box and the sensor sheet becomes folded part and the wiring of the boundary part are damaged. In addition, a firm, thin plastic base sheet may be snapped by bending a sharp angle. Even if the sheet is not folded or snapped at beginning, the sheet can become creased, and if the sheet is repeatedly bent at such positions, stresses become concentrated, which makes it easy for the wiring to become damaged.
In order to pull a sheet-like input/output unit such as the sensor sheet into the connection box, a slit-like opening has to be provided. If the shapes of the edge parts of this slit-like opening is curved and the curvature is small and radius is large, the sheet-like input/output unit can be prevented from being bent sharply, so that the concentration of stresses can be avoided. However, to increase the radius of curvature, it is necessary to increase the area of the edge parts of the slit. In addition, if hooks or projections for fitting and fixing the sheet-like input/output unit are provided on the edges of the slit, it is necessary to provide sufficient plain area for forming the hooks or projections within the edge area. This means that the area of the edge parts of the slit becomes extremely large and complex, so that it is not possible to make the connection box compact.
Instead of providing a means, such as hooks or projections, for fixing the sheet-like input/output unit on the edge of the slit, it is possible to fix the input/output unit and connection box by merely connecting the wiring of the input/output unit to a terminal box inside the connection box, which makes it possible to make the connection box compact. However, when some force acts so as to separate the sheet-like input/output unit and the connection box, such force is concentrated on the joined parts of the wiring and the terminal block inside the connection box, and leads to poor electrical contact.
As mentioned, there are strong demands for the ability to store input/output systems, which include a sheet-like input/output unit, in a compact manner when the systems are not in use. If an input/output system is stored without bending the part where the connection box is attached, it is not possible to make the storage state of the input/output system compact. It is not possible to store the input/output system in an especially compact form by merely folding the sheet-like member. Also, when a relatively firm plastic sheet is used as the base material so as to make it possible for the sheet-like input/output unit to retain its shape to a certain degree, it is not very easy to fold up the sheet-like input/output unit without folding the boundary of connection box.
For the above reasons, it is an object of the present invention to provide an input/output system in which a sheet-like input/output unit is reliably attached to a connection box without the wiring embedded or stuck onto the sheet-like input/output unit becoming damaged when some forces may act thereto. It is a further object of the present invention to provide an input/output system that can be easily and safely (without damage) placed into a compact form during storage.